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<head>
    <meta charset="UTF-8">
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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    <script>
        //forEach迭代（遍历）数组
        var arr=[1,2,3];
        var sum=0;
        arr.forEach(function(value,index,array){
            console.log('每个数组元素:'+value);
            console.log('每个数组元素的索引号:'+index);
            console.log('数组本身:'+array);
            sum+=value;
        });
        console.log(sum);
    </script>
</body>
</html>